Flexible resin pellet and process for producing the same

ABSTRACT

A soft resin pellet of the present invention comprises at least one liquid having a kinematic viscosity at 25° C. ranging from 0.5 to 100,000 cSt and a surface tension at 25° C. ranging from 10 to 50 dyn/cm, for example dimethylpolysiloxane, and at least one kind of fine powder of an average particle diameter of not more than 50 μm, for example calcium stearate, which adhere to the surface of pellets of at least one soft resin (A) selected from the group consisting of the resins (i)-(v) below and having a tensile modulus not higher than 1600 MPa with. The above-mentioned soft resin includes (i) specified ethylene/α-olefin copolymers, (ii) specified propylene/α-olefin copolymers, (iii) unsaturated olefin copolymers constituted of ethylene, an α-olefin of 3-20 carbon atoms, and a (non)conjugated polyene monomer, (iv) ethylene/vinyl acetate copolymers containing vinyl acetate at a content ranging from 5 to 40% by weight, and (v) cycloolefin resins.  
     According to the present invention, the soft resin pellets which are much less sticky and excellent in appearance and handling properties in comparison with conventional pelletized soft resin such as olefin copolymer rubbers can be obtained.

TECHNICAL FIELD

[0001] The present invention relates to a soft resin pellet havingexcellent stick-resistance and having excellent external appearance, anda process for producing the same.

BACKGROUND ART

[0002] Soft resins such as olefin copolymer rubber likeethylene/propylene copolymer rubber, and ethylene/propylene/dienecopolymer rubber are marketed usually in a shape of blocks such asbales.

[0003] Such a block-shaped olefin copolymer rubber have disadvantages oftroublesomeness in taking-out from a storage site, and in supply ortransportation to a molding and processing apparatus, and in weighing.

[0004] Accordingly, the olefin copolymer rubber, if supplied in a pelletform, can be free from the above disadvantages, and has variousadvantages: an extruder of high productivity can be used for preparing acompounded rubber from the pelletized olefin copolymer rubber and acompounding ingredient in place of the less efficient mixer like aBanbury mixer conventionally used for blending an olefin copolymerrubber and a conventional formulating ingredient such as fillers,softeners, and vulcanizing agents.

[0005] However, the above olefin copolymer rubber, even if it ispelletized, will cohere together into blocks during storage owing to thestickiness of the olefin copolymer resin itself to lose the advantagesof the pelletization.

[0006] Even an ethylene/α-olefin copolymer elastomer which is lesssticking at an ordinary temperature can cause cohesion of the pelletswhen the pellets are stored with a load applied thereon or stored in ahigh temperature environment in summer, thereby decreasing the value asa pelletized product.

[0007] Various methods have been disclosed for decreasing the surfacestickiness of the pellets of the inherently sticky olefin copolymerrubber, or preventing cohesion of the pellets of an olefin elastomer,which is less sticky in ordinary temperature, under a load and/or at ahigh temperature. For example, the surface of the rubber pellets iscoated with a silicone oil (Japanese Patent Application Laid-Open No.48(1973)-47934). In another method, a powdery matter such as powderyinorganic substances like talc, silica, and calcium carbonate, or apowdery polyethylene is dusted onto the pellets as an anti-blockingagent to allow the powdery matter to adhere to the sticky pelletsurface.

[0008] However, the coating of the surface of the rubber pellets orelastomer pellets with a silicone oil has a disadvantage that theintended sufficient effects cannot be achieved for the pellets having astrong stickiness. With the latter method, the powdery matter dusted cangive adverse effects in the properties of the rubber in end use, sincethe inorganic material like talc and silica is not compatible with theolefin copolymer rubber. Furthermore, in this method of dusting of apowdery matter, the stickiness-preventing powdery matter is used in anamount from several to ten-and-several percents based on the weight ofthe pellets to prevent substantially the cohesion of the pellets. Such alarge amount of the powdery matter will impair the properties of thetreated olefin copolymer rubber. For example, the rubber properties of avulcanized olefin copolymer rubber dusted with powdery polyethylenebecome deteriorated with increase of the amount of the adhering powderypolyethylene. Further, with this method, dustiness of the pellet surfaceimpairs the external appearance of the pellets and makes the handlingtroublesome.

[0009] An effective countermeasure against the pellet cohesion isdisclosed by the inventors of the present invention (Japanese PatentApplication Laid-Open No. 56(1981)-136347) in which rubber pellets arecoated with a higher fatty acid and/or a salt thereof. This method canprevent the sticking of rubber pellets without impairing the rubberproperties substantially.

[0010] However, the inventors of the present invention found that themethod disclosed in the above Patent Laid-Open Publication cannot allowthe higher fatty acid and/or its salt to adhere stably in a sufficientamount onto rubber pellets since the higher fatty acid and/or its saltis simply mixed with the rubber, and may still cause blocking (cohesion)during storage, or after transportation, weighing, and other treatment.

[0011] The inventors of the present invention, after comprehensiveinvestigation, disclosed a method of preventing the blocking of therubber pellets during storage, in which the olefin copolymer rubberpellets, fine powdery higher fatty acid of 12-30 carbon atoms and/or itssalt, are mixed in the presence of a monohydric alcohol of 1-4 carbonatoms to prepare less sticky rubber pellets (Japanese Patent PublicationNo. 4(1992)-1011). The rubber pellets coated with the higher fatty acidand/or its salt produced according to this method do not cause blocking,even after the pelletized rubber is transported, packed into bags in anamount of 25 kg per bag, and bags are stacked up in 10 stairs for onemonth. In this method, however, the powder-dusted state of the pelletsurface may cause some trouble in handling.

[0012] At the moment, to meet the users' request, appearance of apelletized soft resin which is nonsticky and has excellent appearance,and is easily handleable in comparison with conventional pelletized softresins like olefin copolymer rubbers, and a method of producing the sameis desired.

[0013] The present invention intends to solve the above problems of theprior art techniques, and to provide a soft resin pellet which isnonsticky and has excellent appearance, and is easily handleable incomparison with conventional pelletized soft resins like olefincopolymer rubbers, and a process for production thereof.

DISCLOSURE OF THE INVENTION

[0014] The soft resin pellet of the present invention comprises;

[0015] at least one liquid (B) having a kinematic viscosity at 25° C.ranging from 0.5 to 100,000 cSt (centistokes) and a surface tension at25° C. ranging from 10 to 50 dyn/cm, and

[0016] at least one kind of fine powder (C) of an average particlediameter of not more than 50 μm,

[0017] which adhere to the surface of pellets of at least one soft resin(A) selected from the group consisting of the resins (i)-(v) below andhaving a tensile modulus (YM: ASTM D-658) not higher than 1600 MPa:

[0018] (i) ethylene/α-olefin copolymers produced by copolymerizingethylene and at least one α-olefin of 3-20 carbon atoms,

[0019] (ii) propylene/α-olefin copolymers produced by copolymerizingpropylene and at least one α-olefin of 2 or 4-20 carbon atoms,

[0020] (iii) unsaturated olefin copolymers produced by copolymerizingrandomly ethylene, at least one α-olefin of 3-20 carbon atoms, and atleast one monomer selected from the group consisting of conjugated dienemonomers represented by the chemical formula below and nonconjugatedpolyene monomers:

[0021] (in the chemical formula, R¹ and R² denoting independently ahydrogen atom, an alkyl group of 1-8 carbon atoms, or an aryl grouprespectively, and at least one of R¹ and R² is a hydrogen atom),

[0022] (iv) ethylene/vinyl acetate copolymers containing vinyl acetateat a content ranging from 5 to 40% by weight, and

[0023] (v) cycloolefin resins.

[0024] In the palletized soft resin of the present invention, 50 to20,000 ppm by weight of the above liquid (B) based on the weight of thepellets of the soft resin (A) and 50 to 10,000 ppm by weight of theabove fine powder (C) based on the weight of the pellets of the softresin (A) may adhere to the surface of the pellets of the above softresin (A).

[0025] The process for producing a soft resin pellet of the presentinvention comprises;

[0026] at least one liquid (B) having a kinematic viscosity at 25° C.ranging from 0.5 to 100,000 cSt (centistokes) and a surface tension at25° C. ranging from 10 to 50 dyn/cm, and

[0027] at least one kind of fine powder (C) of an average particlediameter of not more than 50 μm,

[0028] adhering onto the surface of pellets of at least one soft resin(A) selected from the group consisting of the resins (i)-(v) below andhaving a tensile modulus (YM: ASTM D-658) not higher than 1600 MPa:

[0029] (i) ethylene/α-olefin copolymers produced by copolymerizingethylene and at least one α-olefin of 3-20 carbon atoms,

[0030] (ii) propylene/α-olefin copolymers produced by copolymerizingpropylene and at least one α-olefin of 2 or 4-20 carbon atoms,

[0031] (iii) unsaturated olefin copolymers produced by copolymerizingrandomly ethylene, at least one α-olefin of 3-20 carbon atoms, and atleast one monomer selected from the group consisting of conjugated dienemonomers represented by the chemical formula below and nonconjugatedpolyene monomers:

[0032] (in the chemical formula, R¹ and R² denoting independently ahydrogen atom, an alkyl group of 1-8 carbon atoms, or an aryl grouprespectively, and at least one of R¹ and R² is a hydrogen atom),

[0033] (iv) ethylene/vinyl acetate copolymers containing vinyl acetateat a content ranging from 5% to 40% by weight, and

[0034] (v) cycloolefin resins.

[0035] The soft resin (A) may contain an unsaturated carboxylic acid orits derivative at a content ranging from 0.01% to 30% by weight based on100% by weight of the soft resin (A).

[0036] The ethylene/α-olefin copolymer (i) may be a modifiedethylene/α-olefin copolymer (i-b) prepared by grafting an unsaturatedcarboxylic acid or its derivative in a ratio of 0.01% to 30% by weightonto an unmodified ethylene/α-olefin copolymer (i-a).

[0037] The propylene/α-olefin copolymer (ii) may be a modifiedpropylene/α-olefin copolymer (ii-b) prepared by grafting an unsaturatedcarboxylic acid or its derivative in a ratio of 0.01% to 30% by weightonto an unmodified propylene/α-olefin copolymer (ii-a).

[0038] The unsaturated olefin copolymer (iii) may be a modifiedunsaturated olefin copolymer (iii-b) prepared by grafting an unsaturatedcarboxylic acid or its derivative in a ratio of 0.01% to 30% by weightonto an unmodified unsaturated olefin copolymer (iii-a).

[0039] The ethylene/vinyl acetate copolymer (iv) may be a modifiedethylene/vinyl acetate copolymer (iv-b) prepared by grafting anunsaturated carboxylic acid or its derivative in a ratio of 0.01% to 30%by weight onto an unmodified ethylene/vinyl acetate copolymer (iv-a).

[0040] The cycloolefin resin (v) may be a modified cycloolefin resinprepared by grafting an unsaturated carboxylic acid or its derivative ina ratio of 0.01% to 30% by weight onto an unmodified cycloolefin resin.

[0041] The liquid (B) is particularly preferably a dimethylpolysiloxane.

[0042] The fine powder (C) is preferably a fatty acid or a fatty acidderivative. The particularly preferred ones include stearic acid, erucicacid, oleic acid, itaconic acid, and montanic acid; and metal salts,amides, and esters thereof.

BEST MODE FOR CARRYING OUT THE INVENTION

[0043] The soft resin pellet and the process for producing the same ofthe present invention are described below specifically.

[0044] The soft resin pellet of the present invention comprises at leastone liquid (B) having a kinematic viscosity at 25° C. in a specifiedrange and a surface tension at 25° C. in a specified range, and at leastone kind of fine powder (C) having a specified average particlediameter, adhering to the surface of pellets of a specified soft resin(A).

[0045] In the process for producing a soft resin pellet of the presentinvention, the surface of pellets of a specified soft resin (A) isadhered by at least one liquid (B) having a kinematic viscosity at 25°C. in a specified range and a surface tension at 25° C. in a specifiedrange and at least one kind of fine powder (C) having a specifiedaverage particle diameter.

[0046] The soft resin (A), the liquid (B), and the fine powder (C) whichconstitute the palletized soft resin of the present invention and areemployed in the process for producing the same are explained.

Soft Resin (A)

[0047] The soft resin (A) employed in the present invention has atensile modulus (YM: ASTM D-658) of not higher than 1600 MPa, usually inthe range from 1 to 1600 MPa, preferably from 1 to 150 MPa. Such a softresin (A) includes specifically ethylene/α-olefin copolymers (i),propylene/α-olefin copolymers (ii), unsaturated olefin copolymers (iii),ethylene/vinyl acetate copolymers (iv), and cycloolefin resins (v).These soft resins (A) may be used singly or in combination of two ormore thereof. The combinations of two or more resins include those shownbelow.

[0048] (1) combinations of an ethylene/α-olefin copolymer (i) and apropylene/α-olefin copolymer (ii),

[0049] (2) combinations of an ethylene/α-olefin copolymer (i) and anunsaturated olefin copolymer (iii),

[0050] (3) combinations of an ethylene/α-olefin copolymer (i) and anethylene/vinyl acetate copolymer (iv),

[0051] (4) combinations of an ethylene/α-olefin copolymer (i) and acycloolefin resin (v),

[0052] (5) combinations of an ethylene/α-olefin copolymer (i), apropylene/α-olefin copolymer (ii), and an unsaturated olefin copolymer(iii),

[0053] (6) combinations of an ethylene/α-olefin copolymer (i), apropylene/α-olefin copolymer (ii), and an ethylene/vinyl acetatecopolymer (iv),

[0054] (7) combinations of an ethylene/α-olefin copolymer (i), apropylene/α-olefin copolymer (ii), and a cycloolefin resin (v),

[0055] (8) combinations of an ethylene/α-olefin copolymer (i), anunsaturated olefin copolymer (iii), and an ethylene/vinyl acetatecopolymer (iv),

[0056] (9) combinations of an ethylene/α-olefin copolymer (i), anunsaturated olefin copolymer (iii), and a cycloolefin resin (v),

[0057] (10) combinations of an ethylene/α-olefin copolymer (i), anethylene/vinyl acetate copolymer (iv), and a cycloolefin resin (v), and

[0058] (11) combinations of an ethylene/α-olefin copolymer (i), apropylene/α-olefin copolymer (ii), an unsaturated olefin copolymer(iii), an ethylene/vinyl acetate copolymer (iv), and a cycloolefin resin(v).

[0059] The resin (i)-(v) which can be used as the soft resin employed inthe present invention are explained hereunder.

Ethylene/α-Olefin Copolymer (i)

[0060] The ethylene/α-olefin copolymer (i) in the present invention isan ethylene/α-olefin copolymer (i-a) which is derived bycopolymerization of ethylene and an α-olefin of 3-20 carbon atoms, or amodified ethylene/α-olefin copolymer (i-b) which is derived by graftingan unsaturated carboxylic acid or its derivative onto the copolymer(i-a), and has a tensile modulus (YM: ASTM D-658) of not higher than1600 MPa, usually ranging from 1 to 1600 MPa, preferably from 1 to 150MPa.

[0061] The α-olefin having 3-20 carbon atoms to be copolymerized withethylene includes specifically propylene, 1-butene, 1-pentene, 1-hexene,1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene,1-hexadecene, 1-octadecene, 1-nonadecene, 1-eicosene, and4-methyl-1-pentene. These α-olefins may be used singly or in combinationof two or more thereof.

[0062] The ethylene/α-olefin copolymer (i-a) contains preferably theconstituting unit derived from ethylene at a content ranging from 50 to96 mole %, and the constituting unit derived from α-olefin of 3-20carbon atoms at a content ranging from 4 to 50 mole %.

[0063] The composition ratio of the ethylene/α-olefin copolymer (i-a) isusually determined with a sample solution prepared by dissolving about200 mg of the ethylene/α-olefin copolymer uniformly in 1 ml ofhexachlorobutadiene in a test tube of 10 mm φ by measuring the ¹³C—NMRspectrum under conditions of temperature of 120° C., measurementfrequency of 25.05 MHz, spectrum breadth of 1500 Hz, pulse repetitiontime of 4.2 sec, and pulse breadth of 6 μsec.

[0064] The ethylene/α-olefin copolymer (i-a) in the present inventionhas preferably a density (ASTM D 1505) ranging from 0.855 to 0.915g/cm³, preferably from 0.865 to 0.885 g/cm³, and a melt flow rate (MFR;ASTM D 1238, 190° C., load 2.16 kg) ranging from 0.01 to 200 g/10 min,preferably from 0.5 to 40 g/10 min.

[0065] The ethylene/α-olefin copolymer (i-a) includes specificallyethylene/propylene random copolymers, ethylene/1-butene randomcopolymers, ethylene/propylene/1-butene random copolymers,ethylene/1-hexene random copolymers, ethylene/1-butene/1-hexene randomcopolymers, and ethylene /1-octene random copolymers. These copolymersmay be used singly or in combination of two or more thereof.

[0066] The ethylene/α-olefin copolymer (i-a) can be produced by aconventional process with a catalyst such as a vanadium catalyst, atitanium catalyst, or a metallocene catalyst.

[0067] The modified ethylene/α-olefin copolymer (i-b) used as theethylene/α-olefin copolymer (i) in the present invention is a soft resinprepared by grafting an unsaturated carboxylic acid or its derivative(herein after referred to as “unsaturated carboxylic acid or the like”)onto the ethylene/α-olefin copolymer (i-a).

[0068] The amount of the grafting of the unsaturated carboxylic acid orthe like in the modified ethylene/α-olefin copolymer ranges from 0.01%to 30% by weight, preferably from 0.01% to 10% by weight, morepreferably from 0.1 to 2% by weight based on 100% by weight of theethylene/α-olefin copolymer before the graft-modification.

[0069] The unsaturated carboxylic acid includes specifically acrylicacid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid,citraconic acid, crotonic acid, isocrotonic acid, and Nagic acid™(endo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid).

[0070] The derivative of the unsaturated carboxylic acid includes, forexample, halides, amides, imides, acid anhydrides, and eaters of theaforementioned unsaturated carboxylic acids: specifically includingmaleic chloride, maleimide, maleic anhydride, citraconic anhydride,monomethyl maleate, dimethyl maleate, glycidyl maleate, and the like. Ofthese, preferred are unsaturated dicarboxylic acids and acid anhydridesthereof: especially, maleic acid, and Nagic acid™, and acid anhydridethereof.

[0071] The position of grafting of the unsaturated carboxylic acid onthe ethylene/α-olefin copolymer (i-a) is not specially limited. Theunsaturated carboxylic acid or the like may be bonded to any carbon atomof the ethylene/α-olefin copolymer (i-a).

[0072] The graft-modification of the above ethylene/α-olefin copolymer(i-a) by the unsaturated carboxylic acid and the like can be conductedby a conventional graft polymerization process. For example, theethylene/α-olefin copolymer (i-a) is melted, and the unsaturatedcarboxylic acid or the like is added thereto to cause graftpolymerization; or the ethylene/α-olefin copolymer (i-a) is dissolved ina solvent, and the unsaturated carboxylic acid or the like is addedthereto to cause graft polymerization.

[0073] In the above process, the graft monomer such as the unsaturatedcarboxylic acid or the like can be grafted effectively by conducting thegraft polymerization in the presence of a radical initiator. The radicalinitiator is used usually in an amount ranging from 0.001 to 1 part byweight based on 100 parts by weight of the ethylene/α-olefin copolymer(i-a).

[0074] The radical initiator includes organic peroxides, and azocompounds: specifically including benzoyl peroxide, dichlorobenzoylperoxide, dicumyl peroxide, di-t-butyl peroxide,2,5-dimethyl-2,5-di(peroxidobenzoato)hexyne-3,1,4-bis(t-butylperoxyisopropyl)benzene, lauroyl peroxide, t-butylperacetate, 2,5-dimethyl-2,5-di-(t-butylperoxido)hexyne-3,2,5-dimethyl-2,5-di(t-butylperoxido)hexane, t-butyl perbenzoate, t-butylperphenylacetate, t-butyl perisobutyrate, t-butylper-sec-octoate,t-butyl perpivalate, cumyl perpivalate, and t-butyl perdiethylacetate;and azobisisobutyronitrile, and dimethylazoisobutyrate; and so forth.

[0075] Of these radical initiators, preferred are dialkyl peroxides suchas dicumyl peroxide, di-t-butyl peroxide,2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(t-butylperoxy)hexane,1,4-bis(t-butylperoxyisopropyl)benzene.

[0076] The reaction temperature of the graft polymerization with orwithout the radical initiator is in the range usually from 60 to 350°C., preferably from 150 to 300° C.

Propylene/α-Olefin Copolymer (ii)

[0077] The propylene/α-olefin copolymer (ii) in the present invention isa propylene/α-olefin copolymer (ii-a) which is derived bycopolymerization of propylene and an α-olefin of 2 or 4-20 carbon atoms,or a modified propylene/α-olefin copolymer (ii-b) which is derived bygrafting an unsaturated carboxylic acid or its derivative onto thecopolymer (ii-a), and has a tensile modulus (YM: ASTM D-658) of nothigher than 1600 MPa, usually ranging from 1 to 1600 MPa, preferablyfrom 1 to 150 MPa.

[0078] The α-olefin having 2 or 4-20 carbon atoms to be copolymerizedwith propylene includes specifically ethylene, 1-butene, 1-pentene,1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene,1-dodecene, 1-hexadecene, 1-octadecene, 1-nonadecene, 1-eicosene, and4-methyl-1-pentene. These α-olefins may be used singly or in combinationof two or more thereof.

[0079] The propylene/α-olefin copolymer (ii-a) contains preferably theconstituting unit derived from propylene at a content ranging from 50 to95 mole %, and the constituting unit derived from α-olefin of 2 or 4-20carbon atoms at a content ranging from 5 to 50 mole %.

[0080] The composition ratio of the propylene/α-olefin copolymer (ii-a)is usually determined with a sample solution prepared by dissolvinguniformly about 200 mg of the propylene/α-olefin copolymer in 1 ml ofhexachlorobutadiene in a test tube of 10 mm φ by measuring the ¹³C—NMRspectrum under measurement conditions of temperature of 120° C.,measurement frequency of 25.05 MHz, spectrum breadth of 1500 Hz, pulserepetition time of 4.2 sec, and pulse breadth of 6 μsec.

[0081] The propylene/α-olefin copolymer (ii-a) in the present inventionhas preferably a density (ASTM D 1505) ranging from 0.855 to 0.900g/cm³, preferably from 0.855 to 0.885 g/cm³, and a melt flow rate (MFR;ASTM D 1238, 190° C., load 2.16 kg) ranging from 0.01 to 200 g/10 min,preferably from 0.1 to 40 g/10 min.

[0082] The stereoregularity of the polypropylene may be syndiotactic,isotactic, or atactic.

[0083] The propylene/α-olefin copolymer (ii-a) includes specificallypropylene/ethylene copolymers, propylene/1-butene copolymers,propylene/ethylene/1-butene copolymers, and propylene/ethylene /1-octenecopolymers. These copolymers may be used singly or in combination of twoor more thereof.

[0084] The propylene/α-olefin copolymer (ii-a) can be produced by aconventional process with a catalyst such as a vanadium catalyst, atitanium catalyst, or a metallocene catalyst.

[0085] The modified propylene/α-olefin copolymer (ii-b) used as thepropylene/α-olefin copolymer (ii) in the present invention is a softresin prepared by grafting an unsaturated carboxylic acid or itsderivative (hereinafter referred to as “unsaturated carboxylic acid orthe like”) onto the propylene/α-olefin copolymer (ii-a).

[0086] The unsaturated carboxylic acids or the like used in preparationof the modified propylene/α-olefin copolymer (ii-b) are the samecompounds used in preparation of the modified ethylene/α-olefincopolymer (i-b).

[0087] The amount of the grafting of the unsaturated carboxylic acid orthe like in the modified propylene/α-olefin copolymer (ii-b) ranges from0.01 to 30% by weight, preferably from 0.01 to 10% by weight, morepreferably from 0.1 to 2% by weight based on 100% by weight of thepropylene/α-olefin copolymer (ii-a) before the graft-modification.

[0088] The position of grafting of the unsaturated carboxylic acid onthe propylene/α-olefin copolymer (ii-a) is not specially limited. Theunsaturated carboxylic acid or the like may be bonded to any carbon atomof the propylene/α-olefin copolymer (ii-a).

[0089] The graft-modification of the above propylene/α-olefin copolymer(ii-a) by the unsaturated carboxylic acid and the like can be conductedby a conventional graft polymerization process.

[0090] For example, the propylene/α-olefin copolymer (ii-a) is melted,and the unsaturated carboxylic acid or the like is added thereto tocause graft polymerization; or the propylene/α-olefin copolymer (ii-a)is dissolved in a solvent, and the unsaturated carboxylic acid or thelike is added thereto to cause graft polymerization.

[0091] In this process, the graft monomer such as the unsaturatedcarboxylic acid or the like can be grafted effectively by conducting thegraft polymerization in the presence of a radical initiator. The radicalinitiator is used usually in an amount ranging from 0.001 to 1 part byweight based on 100 parts by weight of the propylene/α-olefin copolymer(ii-a).

[0092] The radical initiator includes organic peroxides, and azocompounds. The specific examples of the radical initiator includes thosementioned above as the initiator for the modified ethylene/α-olefincopolymer (i-b).

[0093] The reaction temperature of the graft polymerization with orwithout the radical initiator is in the range usually from 60 to 350°C., preferably from 150 to 300° C.

Unsaturated Olefin Copolymer (iii)

[0094] The unsaturated olefin copolymer (iii) in the present inventionis an unsaturated olefin copolymer (iii-a) which is derived by randomcopolymerization of ethylene, an α-olefin of 3-20 carbon atoms, and aconjugated diene monomer and/or a nonconjugated polyene monomer; or amodified unsaturated olefin copolymer (iii-b) which is derived bygrafting an unsaturated carboxylic acid or its derivative onto thecopolymer (iii-a), and has a tensile modulus (YM: ASTM D-658) of nothigher than 1600 MPa, usually ranging from 1 to 1600 MPa, preferablyfrom 1 to 150 MPa.

[0095] The above α-olefin is not specially limited and may be linear orbranched, provided that it has 3-20 carbon atoms.

[0096] The α-olefin includes specifically propylene, 1-butene,1-pentene, 1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene,3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene,4,4-dimethyl-1-hexene, 4,4-dimethyl-1-pentene, 4-ethyl-1-hexene,3-ethyl-1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene,1-dodecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene,1-octadecene, 1-nonadecene, 1-eicosene, 9-methyl-1-decene,11-methyl-1-dodecene, and 12-ethyl-1-tetradecene. Of these, preferredare propylene, 1-butene, 1-hexene, 1-octene, and 1-decene.

[0097] The α-olefin may be used singly or in combination of two or morethereof.

[0098] The conjugated diene monomer is represented by the chemicalformula below:

[0099] In the above chemical formula, R¹ and R² denotes independently ahydrogen atom, an alkyl group of 1-8 carbon atoms, or an aryl group, atleast one of R¹ and R² being a hydrogen atom.

[0100] The conjugated diene monomer includes specifically 1,3-butadiene,1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 1,3-octadiene,1-phenyl-1,3-butadiene, 1-phenyl-2,4-pentadiene, isoprene,2-ethyl-1,3-butadiene, 2-propyl-1,3-butadiene, 2-butyl-1,3-butadiene,2-pentyl-1,3-butadiene, 2-hexyl-1,3-butadiene, 2-heptyl-1,3-butadiene,2-octyl-1,3-butadiene, and 2-phenyl-1,3-butadiene. Of these,particularly preferred are 1,3-butadiene, and isoprene in view of thecopolymerizability. The conjugated diene monomer may be used singly orin combination of two or more thereof.

[0101] The nonconjugated polyene monomer includes specificallydicyclopentadiene, 1,4-hexadiene, cyclooctadiene, methylenenorbornene,ethylidenenorbornene, 4,8-dimethyl-1,4,8-decatriene,4,8-dimethyl-1,4,9-decatriene, 4,9-dimethyl-1,4,9-decatriene,5,8-dimethyl-1,4,9-decatriene, 5,9-dimethyl-1,4,9-decatriene, and5-vinyl-1,6-octadiene. The preferable nonconjugated polyene monomerincludes aliphatic polyene compounds.

[0102] The unsaturated olefin copolymer (iii-a) has the constitutingunits derived from ethylene, the constituting units derived from anα-olefin of 3-20 carbon atoms, and the constituting units derived from(non)conjugated polyene monomer, the units being bonded randomly to havedouble bond structure of the (non)conjugated monomer, and having themain polymer chain of a substantially linear structure.

[0103] The unsaturated olefin copolymer (iii-a) has a substantiallylinear structure, and contains substantially no gel-like crosslinkingstructure. This is confirmed by the solubleness of this copolymer in anorganic solvent and the substantial absence of the insoluble matter. Forexample, this is confirmed by complete dissolution of the copolymer indecaline at 135° C. in measurement of the intrinsic viscosity [η].

[0104] The unsaturated olefin copolymer (iii-a) employed in the presentinvention contains the constituting units derived from ethylene and theconstituting units derived from α-olefin of 3-20 carbon atoms in a molarratio (ethylene/α-olefin) ranging from 99/1 to 40/60, preferably from95/5 to 50/50, more preferably from 90/10 to 55/45.

[0105] The unsaturated olefin copolymer (iii-a) employed in the presentinvention has preferably a density (ASTM D 1505) ranging from 0.855 to0.880 g/cm³, more preferably from 0.855 to 0.875 g/cm³, and a Mooneyviscosity (ML₁₊₄(100° C.)) ranging from 1 to 99, more preferably from 5to 98.

[0106] The unsaturated olefin copolymer (iii-a) has an intrinsicviscosity [η] at 135° C. in decaline ranging usually from 0.1 to 10dl/g, preferably from 1.0 to 7.0 dl/g. The intrinsic viscosity [η] is ameasure of the molecular weight of the unsaturated olefin copolymer(iii).

[0107] The unsaturated olefin copolymer (iii-a) has an iodine valueranging preferably from 1 to 50, more preferably from 3 to 50, stillmore preferably from 5 to 40.

[0108] In the present invention, the unsaturated olefin copolymer(iii-a) preferably has at least one of the molar ratio of theconstituting units, the intrinsic viscosity [η], and the iodine value inthe aforementioned ranges. More preferably two or more thereof, stillmore preferably all of the molar ratio of the constituting units, theintrinsic viscosity [η], and the iodine value are in the aforementionedranges.

[0109] The unsaturated olefin copolymer (iii-a) has a melting point (Tm)measured by DSC of preferably not higher than 110° C., more preferablynot higher than 70° C., still more preferably not higher than 40° C. Ithas a glass transition temperature (Tg) measured by DSC of preferablynot higher than 25° C., more preferably not higher than 10° C., stillmore preferably not higher than 0° C. Its Mw/Mn value measured by GPC ispreferably not higher than 3.

[0110] The melting point (Tm) and the glass transition temperature (Tg)of the unsaturated olefin copolymer (iii-a) were measured by theprocedure shown below.

[0111] A DSC endothermic curve was derived, and the temperature for thehighest peak was taken as the melting point (Tm).

[0112] In the DSC measurement, the sample in an aluminum pan is heatedat a rate of 10° C./min up to 200° C., kept at 200° C. for 5 minutes,and cooled at a rate of 20° C./min down to −150° C., and then theendothermic curve was derived by raising the temperature at a rate of10° C./min.

[0113] The Mw/Mn of the unsaturated olefin copolymer (iii-a) wasmeasured by GPC (gel permeation chromatography) at 140° C. inorthodichlorobenzene as the solvent.

[0114] The unsaturated olefin copolymer (iii-a) employed in the presentinvention may be a so-called oil-extended rubber, namely a rubberextended with a softener such as a known mineral oil type softener.

[0115] The unsaturated olefin copolymer (iii-a) employed in the presentinvention includes specifically EPDM such asethylene/propylene/1,3-butadiene copolymers, ethylene/propylene/isoprenecopolymers, and ethylene/propylene/5-ethylidene-2-norbornene copolymerrubbers; and oil-extended EPDM such as oil-extendedethylene/propylene/1,3-butadiene copolymers, oil-extendedethylene/propylene/isoprene copolymers, oil-extendedethylene/propylene/5-ethylidiene-2-norbornene copolymer rubbers.

[0116] The aforementioned unsaturated olefin copolymer (iii-a) can beobtained by copolymerization, preferably random copolymerization, ofethylene, α-olefin of 3-20 carbon atoms, and the conjugated dienemonomer represented by the above general chemical formula and/or thenonconjugated polyene in the presence of a known vanadium catalyst or ametallocene catalyst.

[0117] A process for producing the unsaturated olefin copolymer (iii-a)employed in the present invention, and a metallocene catalyst employedin the process are described in detail in Japanese Patent ApplicationLaid-Open No. 11(1999)-228743.

[0118] The modified unsaturated olefin copolymer (iii-b) used as theunsaturated olefin copolymer (iii) in the present invention is a softresin prepared by grafting an unsaturated carboxylic acid or itsderivative (hereinafter referred to as “unsaturated carboxylic acid orthe like”) onto the unsaturated olefin copolymer (iii-a).

[0119] The unsaturated carboxylic acids or the like used in preparationof the modified unsaturated olefin copolymer (iii-b) are the samecompounds used in preparation of the modified ethylene/α-olefincopolymer (i-b).

[0120] The amount of the grafting of the unsaturated carboxylic acid orthe like in the modified unsaturated olefin copolymer (iii-b) rangesfrom 0.01 to 30% by weight, preferably from 0.01 to 10% by weight, morepreferably from 0.1 to 2% by weight based on 100% by weight of theunsaturated olefin copolymer(iii-a) before the graft-modification.

[0121] The position of grafting of the unsaturated carboxylic acid onthe unsaturated olefin copolymer (iii-a) is not specially limited. Theunsaturated carboxylic acid or the like may be bonded to any carbon atomof the unsaturated olefin copolymer (iii-a).

[0122] The graft-modification of the above unsaturated olefin copolymer(iii-a) by the unsaturated carboxylic acid and the like can be conductedby a conventional graft polymerization process.

[0123] For example, the unsaturated olefin copolymer (iii-a) is melted,and the unsaturated carboxylic acid or the like is added thereto tocause graft polymerization; or the unsaturated olefin copolymer (iii-a)is dissolved in a solvent, and the unsaturated carboxylic acid or thelike is added thereto to cause graft polymerization.

[0124] In this process, the graft monomer such as the unsaturatedcarboxylic acid or the like can be grafted effectively by conducting thegraft polymerization in the presence of a radical initiator. The radicalinitiator is used usually in an amount ranging from 0.001 to 1 part byweight based on 100 parts by weight of the unsaturated olefin copolymer(iii-a).

[0125] The radical initiator includes organic peroxides, and azocompounds. The specific examples of the radical initiator includes thosementioned above for the modified ethylene/α-olefin copolymer (i-b).

[0126] The reaction temperature of the graft polymerization with orwithout the radical initiator is in the range usually from 60 to 350°C., preferably from 150 to 300° C.

Ethylene/Vinyl Acetate Copolymer (iv)

[0127] The ethylene/vinyl acetate copolymer (iv) in the presentinvention is an ethylene/vinyl acetate copolymer (iv-a) which is derivedby copolymerization of ethylene and vinyl acetate, or a modifiedethylene/vinyl acetate copolymer (iv-b) which is derived by grafting anunsaturated carboxylic acid or its derivative onto the copolymer (iv-a),and has a tensile modulus (YM: ASTM D-658) of not higher than 1600 MPa,usually ranging from 1 to 1600 MPa, preferably from 1 to 150 MPa.

[0128] The ethylene vinyl acetate copolymer (iv-a) employed in thepresent invention contains vinyl acetate unit at a content rangingpreferably from 5 to 40% by weight, more preferably from 10 to 35% byweight. This ethylene/vinyl acetate copolymer (iv-a) has a melt flowrate (ASTM D 1238, 190° C., load 2.16 kg) ranging usually from 0.1 to 50g/10 min, preferably from 0.3 to 30 g/10 min.

[0129] The modified ethylene/vinyl acetate copolymer (iv-b) used as theethylene/vinyl acetate copolymer (iv) in the present invention is a softresin prepared by grafting an unsaturated carboxylic acid or itsderivative (hereinafter referred to as “unsaturated carboxylic acid orthe like”) onto the ethylene/vinyl acetate copolymer (iv-a).

[0130] The unsaturated carboxylic acids or the like used in preparationof the modified ethylene/vinyl acetate copolymer (iv-b) are the samecompounds used in preparation of the modified ethylene/α-olefincopolymer (i-b).

[0131] The amount of the grafting of the unsaturated carboxylic acid orthe like in the modified ethylene/vinyl acetate copolymer (iv-b) rangesfrom 0.01 to 30% by weight, preferably from 0.1 to 10% by weight, morepreferably from 0.1 to 2% by weight based on 100% by weight of theethylene/vinyl acetate copolymer (iv-a) before the graft-modification.

[0132] The position of grafting of the unsaturated carboxylic acid onthe ethylene/vinyl acetate copolymer (iv-a) is not specially limited.The unsaturated carboxylic acid or the like may be bonded to any carbonatom of the ethylene/vinyl acetate copolymer (iv-a).

[0133] The graft-modification of the above ethylene/vinyl acetatecopolymer (iv-a) by the unsaturated carboxylic acid and the like can beconducted by a conventional graft polymerization process.

[0134] For example, the ethylene/vinyl acetate copolymer (iv-a) ismelted, and the unsaturated carboxylic acid or the like is added theretoto cause graft polymerization; or the ethylene/vinyl acetate copolymer(iv-a) is dissolved in a solvent, and the unsaturated carboxylic acid orthe like is added thereto to cause graft polymerization.

[0135] In this process, the graft monomer such as the unsaturatedcarboxylic acid or the like can be grafted effectively by conducting thegraft polymerization in the presence of a radical initiator. The radicalinitiator is used usually in an amount ranging from 0.001 to 1 part byweight based on 100 parts by weight of the ethylene/vinyl acetatecopolymer (iv-a).

[0136] The radical initiator includes organic peroxides, and azocompounds. The specific examples of the radical initiator includes thosementioned before for the modified ethylene/α-olefin copolymer (i-b).

[0137] The reaction temperature of the graft polymerization with orwithout the radical initiator is in the range usually from 60 to 350°C., preferably from 150 to 300° C.

Cycloolefin Resin (v)

[0138] The cycloolefin resin (v) employed in the present inventionincludes:

[0139] (a-1) ethylene/cycloolefin random copolymers prepared bycopolymerizing ethylene and a cycloolefin represented by General Formula(I) or (II) below,

[0140] (a-2) ring-opening polymerization or copolymerization products ofthe cycloolefin represented by General Formula (I) or (II) below,

[0141] (a-3) hydrogenation products of the above ring-openingpolymerization or copolymerization product of (a-2), and

[0142] (a-4) graft-modified products of (a-1), (a-2), or (a-3),

[0143] the resin having a tensile modulus (YM: ASTM D-658) of not higherthan 1600 MPa, usually in the range from 1 to 1600 MPa, preferably from2 to 150 MPa.

[0144] The cycloolefin which is a monomer represented by General Formula(I) or (II) below and used for preparing the cycloolefin resin in thepresent invention is explained firstly.

[0145] The cycloolefin used for preparing the cycloolefin resin isrepresented by the following General Formula (I) or (II):

[0146] In the above General Formula (I), n denotes a number 0 or 1; mdenotes 0 or a positive integer; k denotes a number 0 or 1; when k is 1,R^(a) and R^(b) are respectively the atom or the hydrocarbon group shownbelow independently, and when k is 0, R^(a) and R^(b) form afive-membered ring by linking the bonds.

[0147] R¹-R¹⁸, R^(a), and R^(b) are respectively a hydrogen atom, ahalogen atom, or a hydrocarbon group; the halogen atom includesfluorine, chlorine, bromine, and iodine.

[0148] The hydrocarbon groups are respectively an alkyl group of 1-20carbon atoms, a cycloalkyl group of 3-15 carbon atoms, or an aromatichydrocarbon group independently. Specifically, the alkyl group includesmethyl, ethyl, propyl, isopropyl, amyl, hexyl, octyl, decyl, dodecyl,and octadecyl. The cycloalkyl group includes cyclohexyl. The aromatichydrocarbon group includes phenyl, and naphthyl. The hydrocarbon groupmay be substituted by a halogen atom.

[0149] Further, in the above General Formula (I), R¹⁵-R¹⁸ mayrespectively be bonded together (in collaboration) to form a monocyclicor polycyclic group, which may have a double bond. Specific example ofthe monocyclic or polycyclic group are shown below.

[0150] In the above exemplified formulas, the numerals 1 and 2 indicaterespectively the carbon atoms where R¹⁵ (R¹⁶) or R¹⁷ (R¹⁸) are bonded.

[0151] R¹⁵ and R^(16,) or R¹⁷ and R¹⁸ may form an alkylidene group. Thealkylidene group is usually an alkylidene group of 2-20 carbon atoms andspecifically includes ethylidene, propylidene, and isopropylidene.

[0152] In the above General Formula (II), p and q denote 0 or a positiveinteger, and r and s denote a number of 0, 1, or 2.

[0153] R²¹-R³⁹ are respectively a hydrogen atom, a halogen atom, ahydrocarbon group, or an alkoxy group independently.

[0154] The halogen atom is the same as in the above General Formula (I).

[0155] The hydrocarbon groups are respectively an alkyl group of 1-20carbon atoms, a halogenated alkyl group of 1-20 carbon atoms, acycloalkyl group of 3-15 carbon atoms, or an aromatic hydrocarbon groupindependently. Specifically, the alkyl group includes methyl, ethyl,propyl, isopropyl, amyl, hexyl, octyl, decyl, dodecyl, and octadecyl.The cycloalkyl group includes cyclohexyl. The aromatic hydrocarbon groupincludes aryl groups and aralkyl groups: specifically phenyl, tolyl,naphthyl, benzyl, and phenylethyl. The alkoxy group includes methoxy,ethoxy, and propoxy.

[0156] The hydrocarbon group and the alkoxy group may be substituted byfluorine, chlorine, bromine, or iodine.

[0157] The carbon atom having R²⁹ and R³⁰ bonded thereto, and the carbonatom having R³³ bonded thereto or the carbon atom having R³¹ bondedthereto may be linked together directly, or indirectly through analkylene group of 1-3 carbon atoms. In the case where the above twocarbon atoms are linked through an alkylene group, the groups R²⁹ andR³³ or the groups R³⁰ and R³¹ form together an alkylene group ofmethylene (—CH₂—), ethylene (—CH₂CH₂—), or propylene (—CH₂CH₂CH₂—).

[0158] When r=s=0, R³⁵ and R³², or R³⁵ and R³⁹ may be bonded together toform a monocyclic or polycyclic aromatic ring. The examples of themonocyclic or polycyclic aromatic ring formed by R³⁵ and R³² for r=s=0are shown below:

[0159] wherein q is the same as in General Formula (II).

[0160] Specific examples of the cycloolefin represented by the aboveGeneral Formula (I) or (II) are shown below.

[0161] The cycloolefin which forms the cycloolefin resin (v) exemplifiedby bicyclo[2.2.1]-2-heptene (=norbornene) shown by the formula below,and derivatives thereof having a hydrocarbon substitutent.

[0162] wherein the numerals 1-7 indicate carbon position numbers.

[0163] The hydrocarbon substituent includes 5-methyl, 5,6-dimethyl,1-methyl, 5-ethyl, 5-n-butyl, 5-isobutyl, 7-methyl, 5-phenyl,5-methyl-5-phenyl, 5-benzyl, 5-tolyl, 5-(ethylphenyl),5-(isopropylphenyl), 5-(biphenylyl), 5-(β-naphthyl), 5-(α-naphthyl),5-(anthryl), and 5,6-diphenyl.

[0164] The other derivatives include bicyclo[2.2.1]-2-heptenederivatives such as cyclopentadiene-acenaphthylene adduct,1,4-methano-1,4,4a,9a-tetrahydrofluorene,1,4-methano-1,4,4a,5,10,10a-hexahydroanthracene, and the like.

[0165] Further the derivatives include tricyclo[4.3.0.1^(2,5)]-3-decene,and derivatives of tricyclo[4.3.0.1^(2,5)]-3-decene such as2-methyltricyclo[4.3.0.1^(2,5)]-3-decene, and5-methyltricyclo[4.3.0.1^(2,5)]-3-decene;tricyclo[4.4.0.1^(2,5)]-3-undecene, and derivatives oftricyclo[4.4.0.1^(2,5)]-3-undecene such as10-methyltricyclo[4.4.0.1^(2,5)]-3-undecene;

[0166] tetracyclo[4.4.0.1^(2,5).1^(7,10)]-3-dodecene shown by thechemical formula below:

[0167] (in the formula, the numerals 1-12 indicating the carbon positionnumbers), and the derivatives thereof having a hydrocarbon substituent,and a compound thereof in which at least one of the hydrogen atoms aresubstituted with another atom.

[0168] The hydrocarbon group or a substituting atom include 8-methyl,8-ethyl, 8-propyl, 8-butyl, 8-isobutyl, 8-hexyl, 8-cyclohexyl,8-stearyl, 5,10-dimethyl, 2,10-dimethyl, 8,9-dimethyl, 8-ethyl-9-methyl,11,12-dimethyl, 2,7,9-trimethyl, 2,7-dimethyl-9-ethyl,9-isobutyl-2,7-dimethyl, 9,11,12-trimethyl, 9-ethyl-11,12-dimethyl,9-isobutyl-11,12-dimethyl, 5,8,9,10-tetramethyl, 8-ethylidene,8-ethylidene-9-methyl, 8-ethylidene-9-ethyl, 8-ethylidene-9-isopropyl,8-ethylidene-9-butyl, 8-n-propylidene, 8-n-propylidene-9-methyl,8-n-propylidene-9-ethyl, 8-n-propylidene-9-isopropyl,8-n-propylidene-9-butyl, 8-isopropylidene, 8-isopropylidene-9-methyl,8-isopropylidene-9-ethyl, 8-isopropylidene-9-isopropyl,8-isopropylidene-9-butyl, 8-chloro, 8-bromo, 8-fluoro, 8,9-dichloro,8-phenyl, 8-methyl-8-phenyl, 8-benzyl, 8-tolyl, 8-(ethylphenyl),8-(isopropylphenyl), 8,9-diphenyl, 8-(biphenylyl), 8-(β-naphthyl),8-(α-naphthyl), 8-(anthryl), and 5,6-diphenyl.

[0169] The derivative includes further

[0170] derivatives of tetracyclo[4.4.0.1^(2,5).1^(7,10)]-3-dodecene,

[0171] pentacyclo[6.5.1.1^(3,6).0^(2,7).0^(9,13)]-4-pentadecene and itsderivative,

[0172] pentacyclo[7.4.0.1^(2,5).1^(9,12).0^(8,13)]-3-pentadecene and itsderivative,

[0173] pentacyclo[8.4.0.1^(2,5).1^(9,12).0^(8,13)]-3-hexadecene and itsderivatives,

[0174] pentacyclo[6.6.1.1^(3,6).0^(2,7).0^(9,14)]-4-hexadecene and itsderivatives,

[0175] hexacyclo[6.6.1.1^(3,6).1^(10,13).0^(2,7).0^(9,14)]-4-heptadeceneand its derivatives,

[0176]heptacyclo[8.7.0.1^(2,9).1^(4,7).1^(11,17).0^(3,8).0^(12,16)]-5-eicoseneand its derivatives,

[0177]heptacyclo[8.7.0.1^(3,6).1^(10,17).1^(12,15).0^(2,7).0^(11,16)]-4-eicoseneand its derivatives,

[0178]heptacyclo[8.8.0.1.^(2,9).1^(4,7).1^(11,18).0^(3,8).0^(12,17)]-5-heneicoseneand its derivatives,

[0179]octacyclo[8.8.0.1^(2,9).1^(4,7).1^(11,18).1^(13,16).0^(3,8).0^(12,17)]-5-docoseneand its derivatives,

[0180] andnonacyclo[10.9.1.1.⁴⁷.1^(13,20).1^(15,18).0^(2,10).0^(3,8).0^(12,21).0^(14,19)]-5-pentacoseneand its derivatives.

[0181] Examples of the cycloolefins represented by General Formula (I)or (II) usable in the present invention are show above. The morespecific structure of these compounds are shown in Japanese PatentApplication Laid-Open No. 7(1995)-145213, Paragraphs [0032] to [0054].The compounds shown there can be used as the cycloolefin in the presentinvention.

[0182] The above cycloolefins represented by General Formula (I) or (II)can be produced by Diels-Alder reaction of a cyclopentadiene and anolefin having a corresponding structure.

[0183] These cycloolefins may be used singly or in combination of two ormore thereof.

[0184] The cycloolefin resin can be produced from the cycloolefinrepresented by the above General Formula (I) or (II) by the process, forexample, disclosed by the inventors of the present invention in JapanesePatent Application Laid-Open Nos. 60(1985)-168708, 61(1986)-120816,61(1986)-115912, 61(1986)-115916, 61(1986)-271308, 61(1986)-272216,62(1987)-252406, and 62(1987)-252407.

[0185] The ethylene/cycloolefin random copolymer (a-1) is a copolymer inwhich ethylene and the aforementioned cycloolefin are randomly bonded,containing the ethylene-derived constituting units at a content rangingusually from 20 to 95 mole %, preferably from 30 to 90 mole %, andcontaining the constituting unit derived from the cycloolefin at acontent ranging usually from 5 to 80 mole %, preferably from 10 to 70mole %. The constitution ratio of the constituting units derived fromethylene to the constituting units derived from the cycloolefin can bemeasured by ¹³C—NMR.

[0186] In this ethylene/cycloolefin random copolymer (a-1), theconstituting units derived from ethylene and the constituting unitsderived from the cycloolefin are bonded in a random arrangement in asubstantially linear structure. The fact that this copolymer has asubstantially linear structure, and does not substantially contain agel-like crosslinking structure is confirmed by the solubleness of thiscopolymer in an organic solvent and the substantial absence of theinsoluble matter: for example, complete dissolution of the copolymer indecaline at 135° C. in measurement of the intrinsic viscosity [η].

[0187] In the ethylene/cycloolefin random copolymer (a-1) in the presentinvention, at least a part of the cycloolefin represented by GeneralFormula (I) or (II) is presumed to constitute the repeating unit shownby General Formula (III) or (IV) below:

[0188] wherein the symbols n, m, k, R¹-R¹⁸, R^(a), and R^(b) denote thesame as in General Formula (I);

[0189] wherein the symbols p, q, r, s, and R²¹-R³⁹ denote the same as inGeneral Formula (II).

[0190] The ethylene/cycloolefin random copolymer (a-1) employed in thepresent invention may contain a constituting unit derived from a thirdcopolymerizable monomer as necessary within the range not to impair theobject of the present invention.

[0191] Such a monomer includes olefins other than ethylene andcycloolefins mentioned above: specifically including linear or branchedα-olefins of 3-20 carbon atoms such as propylene, 1-butene, 1-pentene,1-hexene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene,4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene,4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, 1-octene,1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and1-eicosene; cycloolefins such as cyclobutene, cyclopentene, cyclohexene,3,4-dimethylcyclopentene, 3-methylcyclohexene,2-(2-methylbutyl)-1-cyclohexene, cyclooctene, and3a,5,6,7a-tetrahydro-4,7-methano-1H-indene; and nonconjugated dienessuch as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene,1,7-octadiene, dicyclopentadiene, and 5-vinyl-2-norbornene.

[0192] The additional third monomer may be used singly or in combinationof two or more thereof. In the ethylene/cycloolefin random copolymer(a-1), the constituting unit derived from the above third monomer may becontained at a content of not higher than 20 mole %, preferably nothigher than 10 mole %.

[0193] The ethylene/cycloolefin random copolymer (a-1) employed in thepresent invention can be produced from ethylene and a cycloolefinrepresented by General Formula (I) or (II) by the production processdisclosed in the aforementioned Patent Laid-Open Publication. Preferablythis copolymerization is conducted in a hydrocarbon solvent with acatalyst formed from a vanadium compound and an organoaluminum compoundsoluble in the hydrocarbon solvent to form an ethylene/cycloolefinrandom copolymer.

[0194] In this copolymerization, the catalyst may be a Group-4metallocene catalyst in a solid state. The solid Group-4 metallocenecatalyst mentioned here is composed of a transition metal compoundhaving a ligand having a cyclopentadienyl skeleton, an organoaluminumoxycompound, and an optionally added organoaluminum compound. The Group-4transition metal includes zirconium, titanium, and hafnium. Thetransition metal has a ligand having at least one cyclopentadienylskeleton. The ligand having a cyclopentadienyl skeleton is exemplifiedby cyclopentadienyl, indenyl, tetrahydroindenyl, and fluorenyl which mayhave an alkyl substituent. These groups may be bonded through anothergroup such as an alkylene group. The ligand other than the onecontaining a cyclopentadienyl skeleton includes alkyl, cycloalkyl, aryl,aralkyl, and halogen.

[0195] The organoaluminumoxy compound and the organoaluminum compoundmay be the ones conventionally used in production of olefin resins. Suchsolid Group-4 metallocene catalysts are described, for example, inJapanese Patent Application Laid-Open Nos. 61(1986)-221206,64(1989)-106, and 2(1990)-173112.

[0196] In the ring-opening polymerization or copolymerization product(a-2) of the cycloolefin, at least a portion of the cycloolefinrepresented by General Formula(I) or (II) is presumed to constitute therepeating unit represented by General Formula (V) or (VI) below:

[0197] wherein the symbols n, m, k, R¹-R¹⁸, R^(a), and R^(b) denote thesame as in General Formula (I);

[0198] wherein the symbols p, q, r, s, and R²¹-R³⁹ denote the same as inGeneral Formula (II).

[0199] Such a ring-opening polymerization or copolymerization productcan be produced by the production process disclosed in theaforementioned Patent Laid-Open Publication. For example, thecycloolefin represented by General Formula (I) is polymerized orcopolymerized in the presence of an ring-opening polymerizationcatalyst.

[0200] The ring-opening polymerization catalyst may be a catalystcomposed of a halide, nitrate, or acetylacetonate of a metal such asruthenium, rhodium, palladium, osmium, indium, and platinum, and areducing agent; or a catalyst composed of a halide or acetylacetonate ofa metal such as titanium, palladium, zirconium, and molybdenum, and anorganoaluminum compound.

[0201] The hydrogenation product (a-3) of the ring-openingpolymerization or copolymerization product can be obtained byhydrogenating the ring-opening polymerization or copolymerizationproduct (a-2) in the presence of a known hydrogenation catalyst.

[0202] In the hydrogenation product (a-3) of the ring-openingpolymerization or copolymerization product, at least a portion of thecycloolefin represented by General Formula(I) or (II) is presumed toconstitute the repeating unit represented by General Formula (VII) or(VIII) below:

[0203] wherein the symbols n, m, k, R¹-R¹⁸, R^(a), and R^(b) denote thesame as in General Formula (I);

[0204] wherein the symbols p, q, r, s, and R²¹-R³⁹ denote the same as inGeneral Formula (II).

[0205] The graft-modified product (a-4) of the cycloolefin resin is agraft-modified product of the ethylene/cycloolefin random copolymer(a-1), a graft-modified product of the ring-opening polymerization orcopolymerization product (a-2) of the cycloolefin, or a graft-modifiedproduct of the hydrogenation product (a-3) of the above ring-openingpolymerization or copolymerization product.

[0206] The modifier is usually an unsaturated carboxylic acid or itsderivative (unsaturated carboxylic acid or the like). The unsaturatedcarboxylic acid includes specifically (meth)acrylic acid, maleic acid,fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid,crotonic acid, isocrotonic acid, andendo-cis-bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid (Nagic acid™).The derivative of the unsaturated carboxylic acid includes, for example,unsaturated carboxylic anhydrides, unsaturated carboxylic halides,unsaturated carboxylic acid amides, unsaturated carboxylic acid imides,and esters of the unsaturated carboxylic acids.

[0207] Specific examples of the unsaturated carboxylic acid derivativesinclude maleic anhydride, citraconic anhydride, maleic chloride,maleimide, monomethyl maleate, dimethyl maleate, and glycidyl maleate.

[0208] Of these modifiers, preferred are α,β-unsaturated dicarboxylicacid and α,β-unsaturated dicarboxylic anhydride: especially, maleicacid, and Nagic acid™, and acid anhydride thereof. The modifier may beused singly or in combination of two or more thereof.

[0209] The amount of grafting of the unsaturated carboxylic acid or thelike in the graft-modified cycloolefin resin used in the presentinvention is in the range from 0.01 to 30% by weight, preferably from0.1 to 10% by weight, more preferably from 0.1 to 2% by weight based on100% by weight of the cycloolefin resin before the graft-modification.

[0210] The graft-modified cycloolefin resin may be produced bygraft-polymerizing a modifier onto the cycloolefin resin to attain anintended grafting degree, or otherwise by preparing preliminarily amodified product of high modification degree and blending this modifiedproduct with the unmodified cycloolefin resin.

[0211] The graft-modified cycloolefin resin can be produced from thecycloolefin resin and the modifier by any known polymer modificationprocess. For example, a cycloolefin resin is melted and a modifier isadded thereto to cause graft polymerization (reaction), or a cycloolefinresin is dissolved in a solvent and a modifier is added to the solutionto cause graft reaction.

[0212] The graft reaction is conducted usually at a temperature rangingfrom 60 to 350° C. The graft reaction can be conducted in the presenceof a radical initiator such as organic peroxides and azo compounds.

[0213] The cycloolefin resin (v) may be any of the resins (a-1), (a-2),(a-3),and (a-4), or combination of two or more thereof in the presentinvention.

[0214] The cycloolefin resin (v) has a melt flow rate (MFR: ASTM D 1238,260° C., load 2.16 kg) ranging preferably from 0.1 to 60 g/10 min, morepreferably from 2 to 50 g/10 min, still more preferably from 10 to 30g/10 min.

Liquid (B)

[0215] The liquid (B) used in the present invention has a kinematicviscosity (JIS K-2283) at 25° C. ranging from 0.5 to 100,000 cSt(centistokes), preferably from 100 to 5,000 cSt, more preferably from200 to 1,000 cSt; and a surface tension (by capillary-rise method) at25° C. ranging from 10 to 50 dyn/cm, preferably from 10 to 40 dyn/cm,more preferably from 10 to 30 dyn/cm. Such a liquid (B) includesspecifically silicone oils, glycol, mineral oils, and higher alcohols.The silicone oils include specifically polysiloxanes having therepeating unit represented by the formula below:

[0216] wherein R and R′ denote respectively an alkyl group, an arylgroup, or these groups having the hydrogen atom substituted by a halogenatom or the like independently. R and R′ may the same or different. Apart of the groups R or R′ may be substituted by a hydroxyl group or analkoxy group.

[0217] The alkyl group includes specifically methyl, ethyl, propyl,isopropyl, n-butyl, s-butyl, and t-butyl.

[0218] The aryl group includes specifically phenyl, and tolyl.

[0219] The halogen atom includes specifically atoms of fluorine,chlorine, bromine, and iodine.

[0220] The alkoxy group includes specifically methoxy, ethoxy, propoxy,and isopropoxy.

[0221] Of these polysiloxanes, particularly preferred aredimethylpolysiloxanes.

[0222] The liquid (B) above may be used singly or in combination of twoor more thereof in the present invention.

Fine Powder (C)

[0223] The fine powder (C) in the present invention has an averageparticle diameter of not larger than 50 μm: usually in the range from0.1 to 50 μm, preferably from 1 to 30 μm, more preferably from 1 to 25μm. The average particle diameter was measured by observation by SEM(scanning electron microscopy) or optical microscopy.

[0224] The fine powder (C) preferably used in the present inventionincludes specifically inorganic fillers, organic fillers, fatty acids,and fatty acid derivatives.

[0225] The inorganic filler includes specifically silica,silica-alumina, diatomite, alumina, calcium carbonate, titanium oxide,magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide,magnesium hydroxide, boron hydroxide, basic magnesium carbonate,dolomite, calcium sulfate, potassium titanate, barium carbonate, bariumsulfate, calcium sulfite, talc, clay, mica, asbestos, calcium silicate,montmorillonite, bentonite, graphite, aluminum powder, and molybdenumsulfide. The inorganic filler may be used singly or in combination oftwo or more thereof.

[0226] The fatty acid used preferably in the present invention includesusually saturated or unsaturated higher fatty acids of 12-30 carbonatoms, specifically including lauric acid, myristic acid, palmitic acid,margaric acid, stearic acid, behenic acid, oleic acid, linolenic acid,α-eleostearic acid, β-eleostearic acid, and α-linolenic acid. Of thesestearic acid is preferred.

[0227] The fatty acid derivative used preferably in the presentinvention includes salts of the aforementioned higher fatty acids:specifically sodium salts, potassium salts, magnesium salts, calciumsalts, zinc salts, aluminum salts, iron salts, and lithium salts. Ofthese, stearic acid salts are preferred. The higher fatty acidderivative includes amides and esters of the higher fatty acids. Ofthese derivatives, preferred are amides and esters of stearic acid,erucic acid, oleic acid, itaconic acid, and montanic acid.

[0228] The above fatty acids or fatty acid derivatives may be usedsingly or in combination of two or more thereof.

Process for Producing Pellets

[0229] The soft resin pellets of the present invention can be obtainedby allowing the above liquid (B) and the above fine powder (C) to adhereonto the surface of the pellets of the aforementioned soft resin (A). Inthe process for producing the soft resin pellets of the presentinvention, it is preferable that the pellets of the soft resin (A) andthe liquid (B) are mechanically mixed to allow the liquid (B) to adhereonto the pellet surface and subsequently the fine powder (C) is dustedetc. onto the surface of the pellets to allow the powder adhere thereto.

[0230] Such pellets can be produced, for example, by any of the twomethods below.

[0231] (1) The pellets of the soft resin (A) and the liquid (B) aremechanically mixed by a conventional method to allow the liquid (B) toadhere onto the pellet surface, and subsequently, fine powder (C) isdusted onto the surface of the pellets to allow the liquid (B) and thefine powder (C) to adhere to the pellet surface of the soft resin (A).

[0232] (2) The soft resin (A) is pelletized by melt extrusion, throughan extruder equipped with a pelletizer of a so-called under-water-cuttype, into water containing the liquid (B) finely dispersed therein byaddition of a known surfactant (e.g., soap). Thereby the liquid (B) isallowed to adhere to the surface of the pellets. Then the fine powder(C) is dusted onto the pellet surface to allow the liquid (B) and thefine powder (C) to adhere to the pellets of the soft resin (A).

[0233] Thus, the pellet surface of the soft resin (A) is coated with theliquid (B) and the fine powder (C).

[0234] In the above method (1), the liquid (B) is allowed to adhere onthe surface of the pellets of the soft resin (A) in an amount rangingusually from 50 to 20,000 ppm by weight, preferably from 100 to 2,000ppm by weight based on the weight of the pellets of the soft resin (A),and the fine powder (C) is allowed to adhere on the surface of thepellets of the soft resin (A) in an amount ranging usually from 50 to10,000 ppm by weight, preferably from 500 to 5,000 ppm by weight basedon the weight of the pellets of the soft resin (A).

[0235] In the above method (2), the concentration of the liquid (B) inthe water ranges usually from 500 to 50,000 ppm by weight, preferablyfrom 500 to 5,000 ppm by weight, and the surfactant is used in an amountranging usually from 1 to 100 parts by weight, preferably from 2 to 20parts by weight based on 100 parts by weight of the liquid (B). With theabove amount of the surfactant, the liquid (B) can be finely dispersedin water.

[0236] In the above method (2), the liquid (B) is allowed to adhere onthe surface of the pellets of the soft resin (A) in an amount rangingusually from 50 to 20,000 ppm by weight, preferably from 100 to 2,000ppm by weight based on the weight of the pellets of the soft resin (A),and the fine powder (C) is allowed to adhere on the surface of thepellets of the soft resin (A) in an amount ranging usually from 50 to10,000 ppm by weight, preferably from 500 to 5,000 ppm by weight basedon the weight of the pellets of the soft resin (A).

[0237] In the soft resin pellets of the present invention, at least apart of the pellet surface preferably has a structure comprising theliquid (B) layer and the fine powder (C) dispersed in the layer. It canbe confirmed visually, for example.

[0238] Further, in the soft resin pellets of the present invention, itis preferable that the liquid (B) adheres to the whole surface of thepellets of the soft resin (A). It can be confirmed visually, forexample.

[0239] According to the present invention, a soft resin pellet which isexcellent in nonsticking properties (retardation of pellet blocking),appearance, and handling properties in comparison with soft resinpellets of conventional olefin copolymer rubbers, and the productionprocess thereof can be provided.

EXAMPLES

[0240] The present invention is explained by reference to exampleswithout limiting the invention in any way.

[0241] The pellet blocking test was conducted in the present inventionaccording to the procedure shown below.

Pellet Blocking Test

[0242] A 60 g portion of the sample pellets (average weight of onepellet: about 35 mg) is put into a polyethylene pouch of 120 mm×210 mm.The pouch was folded in three, and the open end was sealed with acellophane adhesive tape.

[0243] The three-folded pouches prepared as above were stacked in twostairs, and thereon a load of 90 g/cm² was applied in condition of 40°C. After keeping this state for 24 hours, the three-folded pouches wereopened to take out the pellets. The nonsticking (noncohering) state ofthe pellets was rated on 10 grades as below.

[0244] (Evaluation Standard for Nonsticking Properties of Pellets)

[0245] 10: No blocking is observed,

[0246] 7: Blocked pellets collapse by self-weight,

[0247] 5: Blocked pellets can be disintegrated readily by hand,

[0248] 3: Blocked pellets can be disintegrated by strong push by hand,

[0249] 1: Pellets cohere together into a bale state.

[0250] The external appearance was examined visually and was evaluatedon two grades as below.

[0251] (Evaluation of External Appearance)

[0252] Good (O): No surface dustiness (the added dust (C) being notrecognizable visually)

[0253] Bad (X): Dustiness (the added dust (C) being recognizablevisually)

[0254] In Examples, the silicone oil, and the calcium stearate adheringto the pellet surface are determined as below.

Determination of Silicone Oil

[0255] A known mount of the pellets were washed with methyl isobutylketone (MIBK), a solvent for silicone oil. The washing solution wascollected. The collected washing solution was subjected to fluorescentX-ray analysis. The quantity of the silicone oil was derived from theintensity of the X-ray of Si by reference to a preliminarily preparedcalibration curve.

Determination of Calcium Stearate

[0256] A known mount of the pellets were subjected to fluorescent X-rayanalysis. The quantity of the calcium stearate was derived from theintensity of the X-ray of Ca by reference to a preliminarily preparedcalibration curve.

[0257] Incidentally, the silicone oil and the calcium stearate can bequantitatively determined by washing 100 g of the pellets with methanol,collecting the washing methanol, evaporating the methanol component, anddetermining silicon and calcium in the evaporation residue by metalanalysis.

EXAMPLE 1

[0258] An ethylene/1-butene copolymer (EBR) of density (ASTM D1505)=0.865 g/cm³, MFR (ASTM D 1238, 190° C., load 2.16 kg)=4 g/10 min,ethylene content=82 mole %, and tensile modulus (YM)=9.5 MPa was kneadedand pelletized at 200° C. with a single screw extruder. A portion of 100parts by weight of the pelletized copolymer, 0.1 parts by weight of asilicone oil (trade name SH200, produced by Dow Corning Toray SiliconeCo., Ltd.; kinematic viscosity (20° C.)=500 cSt, surface tension (20°C.)=20 dyn/cm) were mixed mechanically by a Henschel mixer.

[0259] The entire of the obtained soft resin pellets coated with thesilicone oil was mixed with 0.35 parts by weight of calcium stearatehaving an average particle diameter of 20 μm mechanically by a Henschelmixer.

[0260] The resulting pellets contained silicone oil adhering in anamount of 990 ppm by weight, and calcium stearate adhering in an amountof 3,350 ppm by weight.

[0261] This soft resin pellet was subjected to pellet blocking test bythe procedure mentioned above. Table 1 shows the results.

Comparative Example 1

[0262] The experiment was conducted in the same manner as in Example 1,except that the mechanical mixing of the silicone oil and the calciumstearate with the soft resin pellet was not conducted. Table 1 shows theresults.

Comparative Example 2

[0263] The experiment was conducted in the same manner as in Example 1,except that the mechanical mixing of the calcium stearate with the softresin pellet was not conducted. Table 1 shows the results.

Comparative Example 3

[0264] The experiment was conducted in the same manner as in Example 1,except that the mechanical mixing of the silicone oil with the softresin pellet was not conducted. Table 1 shows the results.

EXAMPLE 2

[0265] A propylene/ethylene copolymer (PER) of density (ASTM D1505)=0.858 g/cm³, MFR (ASTM D 1238, 190° C., load 2.16 kg)=2 g/10 min,propylene content=60 mole %, and tensile modulus (YM)=3.5 MPa waskneaded and pelletized at 200° C. with a single screw extruder. Aportion of 100 parts by weight of the pelletized copolymer, 0.1 parts byweight of a silicone oil (trade name SH200, produced by Dow CorningToray Silicone Co., Ltd.; kinematic viscosity (20° C.)=500 cSt, surfacetension (20° C.)=20 dyn/cm) were mixed mechanically by a Henschel mixer.

[0266] The entire of the obtained soft resin pellets coated with thesilicone oil was mixed with 0.35 parts by weight of calcium stearatehaving an average particle diameter of 20 μm mechanically by a Henschelmixer.

[0267] The resulting pellets contained silicone oil adhering in anamount of 980 ppm by weight, and calcium stearate adhering in an amountof 3,400 ppm by weight.

[0268] This soft resin pellet was subjected to pellet blocking test bythe procedure mentioned above. Table 1 shows the results.

Comparative Example 4

[0269] The experiment was conducted in the same manner as in Example 2,except that the mechanical mixing of the calcium stearate with the softresin pellet was not conducted. Table 1 shows the results.

Comparative Example 5

[0270] The experiment was conducted in the same manner as in Example 2,except that the mechanical mixing of the silicone oil with the softresin pellet was not conducted. Table 1 shows the results.

EXAMPLE 3

[0271] An oil-extended ethylene/propylene/5-ethylidene-2-norbornenecopolymer (oil-extended EPDM) of density (ASTM D 1505)=0.87 g/cm³,Mooney viscosity [ML₁₊₄(100° C.)]=74, intrinsic viscosity (135° C. indecaline)=3 dl/g, ethylene/propylene/5-ethyidene-2-norbornene (molarratio)=78/15.8/6.2 mole %, iodine value=13, tensile modulus (YM)=2 MPa,extending oil=40 phr, and softener (trade name W-380, produced byIdemitsu Petrochemical Co.) was employed. This copolymer was kneaded andpelletized at 200° C. with a single screw extruder. A portion of 100parts by weight of the pelletized copolymer, 0.1 parts by weight of asilicone oil (trade name SH200, produced by Dow Corning Toray SiliconeCo., Ltd.; kinematic viscosity (20° C.)=500 cSt, surface tension (20°C.)=20 dyn/cm) were mixed mechanically by a Henschel mixer.

[0272] The entire of the obtained soft resin pellets coated at thesurface with the silicone oil was mixed with 0.35 parts by weight ofcalcium stearate having an average particle diameter of 20 μmmechanically by a Henschel mixer.

[0273] The resulting pellets contained silicone oil adhering in anamount of 950 ppm by weight, and calcium stearate adhering in an amountof 3,200 ppm by weight.

[0274] This soft resin pellet was subjected to pellet blocking test bythe procedure mentioned above. Table 1 shows the results.

Comparative Example 6

[0275] The experiment was conducted in the same manner as in Example 3,except that the mechanical mixing of the calcium stearate with the softresin pellet was not conducted. Table 1 shows the results.

Comparative Example 7

[0276] The experiment was conducted in the same manner as in Example 3,except that the mechanical mixing of the silicone oil with the softresin pellet was not conducted. Table 1 shows the results.

EXAMPLE 4

[0277] An ethylene/1-octene copolymer (EOR) of density (ASTM D1505)=0.87 g/cm³, MFR (ASTM D 1238, 190° C., load 2.16 kg)=2 g/10 min,ethylene content=85 mole %, and tensile modulus (YM)=8 MPa was used forpellet formation.

[0278] This ethylene/1-octene copolymer (EOR) was fed to an extruderequipped with a pelletizer. The ethylene/1-octene copolymer (EOR) wasmelt-extruded at a rate of 5 tons/h into a circulation box in whichcooling water was circulated at a flow rate of 140 tons/h, and there themelt-extruded resin was cut continuously by a rotating blade intopellets, and the soft resin pellet was conveyed to a centrifugaldehydrator. The temperature of the circulating water was controlled tobe at 5° C. for the purpose of preventing the cohesion of the obtainedsoft resin pellets. For the same purpose, a silicone oil (trade nameSH200, produced by Dow Corning Toray Silicone Co., Ltd.; kinematicviscosity (20° C.)=500 cSt, surface tension (20° C.)=20 dyn/cm) wasadded at a rate of 10 kg/h, and for dispersing this silicone oil, asurfactant (Bulronick F108, produced by Asahi Denka Kogyo K.K.) wasadded at a rate of 120 g/h.

[0279] After the soft resin pellets and water were separated by thecentrifugal dehydrator, the pellets were conveyed to a Henschel mixer,where calcium stearate in an amount of 3,500 ppm by weight was mixedwith the pellets.

[0280] The pellets contained the silicone oil adhering in an amount of1,100 ppm by weight, and the calcium stearate adhering in an amount of3,000 ppm by weight.

[0281] This soft resin pellet was subjected to the pellet blocking testin the manner mentioned above. The blocking state of the pellets wasevaluated to be grade 7. The pellets did not show a powder-dusted stateon the surface and the external appearance of the pellets was good.

[0282] Table 1 shows the test results.

[0283] Any pellets obtained in Example 1 to 4 had silicone oil adheringto the whole surface thereof. In the silicone oil, calcium stearateexisted dispersively and such structure was confirmed visually. TABLE 1Silicone Calcium Soft oil (wt stearate Blocking resin ppm) (wt ppm) testresult Appearance Example 1 E B R 990 3,350 7 ◯ Comparative E B R 0 0 3◯ Example 1 Comparative E B R 980 0 5 ◯ Example 2 Comparative E B R 03,350 5 X Example 3 Example 2 E B R 980 3,400 5 ◯ Comparative E B R 9800 1 ◯ Example 4 Comparative E B R 0 3,300 3 X Example 5 Example 3 O-ex950 3,200 5 ◯ EPDM* Comparative O-ex 960 0 1 ◯ Example 6 EPDM*Comparative O-ex 0 3,250 3 X Example 7 EPDM* Example 4 EOR 1,100 3,000 7◯

What is claimed is:
 1. A soft resin pellet comprising; at least oneliquid (B) having a kinematic viscosity at 25° C. ranging from 0.5 to100,000 cSt (centistokes) and a surface tension at 25° C. ranging from10 to 50 dyn/cm, and at least one kind of fine powder (C) of an averageparticle diameter of not more than 50 μm, which adhere to the surface ofpellets of at least one soft resin (A) selected from the groupconsisting of the resins (i)-(v) below and having a tensile modulus (YM:ASTM D-658) not higher than 1600 MPa: (i) ethylene/α-olefin copolymersproduced by copolymerizing ethylene and at least one α-olefin of 3-20carbon atoms, (ii) propylene/α-olefin copolymers produced bycopolymerizing propylene and at least one α-olefin of 2 or 4-20 carbonatoms, (iii) unsaturated olefin copolymers produced by copolymerizingrandomly ethylene, at least one α-olefin of 3-20 carbon atoms, and atleast one monomer selected from the group consisting of conjugated dienemonomers represented by the chemical formula below and nonconjugatedpolyene monomers:

(in the chemical formula, R¹ and R² denoting independently a hydrogenatom, an alkyl group of 1-8 carbon atoms, or an aryl group, and at leastone of R¹ and R² is a hydrogen atom) (iv) ethylene/vinyl acetatecopolymers containing vinyl acetate at a content ranging from 5 to 40%by weight, and (v) cycloolefin resins.
 2. The soft resin pelletaccording to claim 1, wherein 50-20,000 ppm by weight of the aboveliquid (B) based on the weight of the pellets of the soft resin (A) and50-10,000 ppm by weight of the above fine powder (C) based on the weightof the pellets of the soft resin (A) adhere to the surface of thepellets of the soft resin(A).
 3. A process for producing a soft resinpellet, comprising at least one liquid (B) having a kinematic viscosityat 25° C. ranging from 0.5 to 100,000 cSt (centistokes) and a surfacetension at 25° C. ranging from 10 to 50 dyn/cm, and at least one kind offine powder (C) of an average particle diameter of not more than 50 μm,adhering onto the surface of pellets of at least one soft resin (A)selected from the group consisting of the resins (i)-(v) below andhaving a tensile modulus (YM: ASTM D-658) not higher than 1600 MPa: (i)ethylene/α-olefin copolymers produced by copolymerizing ethylene and atleast one α-olefin of 3-20 carbon atoms, (ii) propylene/α-olefincopolymers produced by copolymerizing propylene and at least oneα-olefin of 2 or 4-20 carbon atoms, (iii) unsaturated olefin copolymersproduced by copolymerizing randomly ethylene, at least one α-olefin of3-20 carbon atoms, and at least one monomer selected from the groupconsisting of conjugated diene monomers represented by the chemicalformula below and nonconjugated polyene monomers:

(in the chemical formula, R¹ and R² denoting independently a hydrogenatom, an alkyl group of 1-8 carbon atoms, or an aryl group, and at leastone of R¹ and R² is a hydrogen atom) (iv) ethylene/vinyl acetatecopolymers containing vinyl acetate at a content ranging from 5 to 40%by weight, and (v) cycloolefin resins.
 4. The process for producing asoft resin pellet according to claim 3, wherein the soft resin (A)contains an unsaturated carboxylic acid or its derivative at a contentranging from 0.01 to 30% by weight based on 100% by weight of the softresin (A).
 5. The process for producing a soft resin pellet according toclaim 3, wherein the ethylene/α-olefin copolymer (i) is a modifiedethylene/α-olefin copolymer (i-b) prepared by grafting an unsaturatedcarboxylic acid or derivative thereof in a ratio of 0.01 to 30% byweight onto an unmodified ethylene/α-olefin copolymer (i-a).
 6. Theprocess for producing a soft resin pellet according to claim 3, whereinthe propylene/α-olefin copolymer (ii) is a modified propylene/α-olefincopolymer (ii-b) prepared by grafting an unsaturated carboxylic acid orits derivative in a ratio of 0.01 to 30% by weight onto an unmodifiedpropylene/α-olefin copolymer (ii-a).
 7. The process for producing a softresin pellet according to claim 3, wherein the unsaturated olefincopolymer (iii) is a modified unsaturated olefin copolymer (iii-b)prepared by grafting an unsaturated carboxylic acid or its derivative ina ratio of 0.01 to 30% by weight onto an unmodified unsaturated olefincopolymer (iii-a).
 8. The process for producing a soft resin pelletaccording to claim 3, wherein the ethylene/vinyl acetate copolymer (iv)is a modified ethylene/vinyl acetate copolymer (iv-b) prepared bygrafting an unsaturated carboxylic acid or its derivative in a ratio of0.01 to 30% by weight onto an unmodified ethylene/vinyl acetatecopolymer (iv-a).
 9. The process for producing a soft resin pelletaccording to claim 3, wherein the cycloolefin resin (v) is a modifiedcycloolefin resin prepared by grafting an unsaturated carboxylic acid orits derivative in a ratio of 0.01 to 30% by weight onto an unmodifiedcycloolefin resin.
 10. The process for producing a soft resin pelletaccording to claim 3, wherein the liquid (B) is a dimethylpolysiloxane.11. The process for producing a soft resin pellet according to claim 3,wherein the fine powder (C) is a fatty acid or a fatty acid derivative.12. The process for producing a soft resin pellet according to claim 11,wherein the fatty acid or the fatty acid derivative is selected fromstearic acid, erucic acid, oleic acid, itaconic acid, and montanic acid;and metal salts, amides, and esters thereof.